Question: Khan.scratchpad.disable(); For every level Christopher completes in his favorite game, he earns $670$ points. Christopher already has $120$ points in the game and wants to end up with at least $3950$ points before he goes to bed. What is the minimum number of complete levels that Christopher needs to complete to reach his goal?
Explanation: To solve this, let's set up an expression to show how many points Christopher will have after each level. Number of points $=$ $ $ Levels completed $\times$ Points per level $+$ Starting points Since Christopher wants to have at least $3950$ points before going to bed, we can set up an inequality. Number of points $\geq 3950$ Levels completed $\times$ Points per level $+$ Starting points $\geq 3950$ We are solving for the number of levels to be completed, so let the number of levels be represented by the variable $x$ We can now plug in: $x \cdot 670 + 120 \geq 3950$ $ x \cdot 670 \geq 3950 - 120 $ $ x \cdot 670 \geq 3830 $ $x \geq \dfrac{3830}{670} \approx 5.72$ Since Christopher won't get points unless he completes the entire level, we round $5.72$ up to $6$ Christopher must complete at least 6 levels.